Support ESS-style comment symbol ##' as well

[eddelbuettel]

When one uses Emacs and ESS, it becomes second nature to use ##' as the dual # is different from #: the latter gets (by convention) indented to middle of the screen (for comments following a statement, typically) whereas ##' stays flush.

In fact, when one writes a simple function, say

emptydemo <- function(foo = 42L) {
    foo
}

and then asks for the documentation template (via C-c C-o C-c, or via the menu, or via the function) then one gets

##' .. content for \description{} (no empty lines) ..
##'
##' .. content for \details{} ..
##' @title 
##' @param foo 
##' @return 
##' @author Dirk Eddelbuettel
emptydemo <- function(foo = 42L) {
    foo
}

(where one can question the wisdom of doing @title by tag and @detail and @description by placement, but that is how they role; addiing @author is) which is clearly using ##'. That used to stop tinyrox in its tracks.

Following the PR if I invoke trox.r (as I live on the command-line for these things) we get

% tinyrox says don't edit this manually, but it can't stop you!
\name{emptydemo}
\alias{emptydemo}
\title{}
\usage{
emptydemo(foo = 42L)
}
\arguments{
\item{foo}{}
}
\value{

}
\description{
.. content for \details{} ..
}

and life is good. I looked for the exising ^#' regular expressions (and variants) and made them ^##?' which should allow for everything that was done before (when ? acts as 'add zero instances of the preceding symbol' as well as the desired new feature demonstrated here (when ? adds exactly one).

[eddelbuettel]

Thanks for the follow-up, and merge!

[TroyHernandez]

Thanks for the PR!